Based on the InputOutput Tables of China, this paper gives a deep insight of the distribution and changing characters of export addedvalue rate of China’s industries after China joining WTO by the method of kernel density function. The results show that as a whole, all the export addedvalue rates of China’s three industries are showing a trend toward rapid decline at first, then moderate rebound and finally stability, while each industry varies in direction, strength and time. Using kernel density function decomposition approach, it finds that the leading cause of dynamic change is average effect (a decrease in the overall export valueadded rate), next is residual effect (heterogeneity products division with extremely high or low export value added rate), and the last is variance effect (uneven export valueadded rate in all products). Thus, the promotion of export valueadded increase needs to boost the holistic development of all industries and to pay attention to individual feature of different industries.